Liang Weidong, a deputy director in Pengshan's publicity department, said in an interview on China National Radio that authorities first heard about the ducks in southwest China on Tuesday. They were found in more than 50 woven bags. The cause of death was undetermined because many of the ducks had already decomposed, according to the BBC.

An initial investigation suggested that the dead birds had come from upstream and were not dumped by local Pengshan farmers.

Although officials have yet to explain the waterfowl deaths, the Wall Street Journal has speculated that the pig bodies found earlier may have been the result of “deadstock disposal” practices. Now that the country is taking more severe measures against the illegal sale of tainted pork, the lack of black-market buyers has dwindled and farmers are left with a surplus of contaminated pigs.

"Ever since the police have stepped up efforts to crack down on the illicit market of sick pigs since last year, no one has come here to buy dead pigs, and the problem of pig dumping is worse than ever this year," a villager told the state-run Jiaxing Daily newspaper, reports CBS.

The news of the ducks has triggered criticism and consternation from some residents. Users on weibo, China's version of Twitter, have taken to the social networks to voice their concerns. Wrote weibo user Baby Lucky, "Dead pigs, dead ducks ... this soup is getting thicker and thicker."